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AP Chemistry Practice Quiz: Photoelectron Spectroscopy

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: June 2026

Test your understanding with short quizzes. This quiz has 7 questions to check your progress.

Question 1 of 7

According to the principles of photoelectron spectroscopy (PES), what information is determined by the position of a peak along the energy axis of the spectrum?

All Questions (7)

According to the principles of photoelectron spectroscopy (PES), what information is determined by the position of a peak along the energy axis of the spectrum?

A) The number of electrons in a specific subshell.

B) The total number of electrons in the atom.

C) The binding energy of electrons in a specific subshell.

D) The atomic mass of the element.

Correct Answer: C

The provided content explicitly states that in a PES spectrum, 'peak position relates to the binding energy of an electron in a subshell.' The height of the peak, not its position, relates to the number of electrons.

In the photoelectron spectrum of a neutral neon atom (Ne), the peak representing the 2p subshell is expected to be how many times taller than the peak representing the 1s subshell?

A) Two times taller

B) Three times taller

C) Six times taller

D) The same height

Correct Answer: B

The ground-state electron configuration of Neon is 1s²2s²2p⁶. The content states that 'peak height is proportional to the number of electrons in that subshell.' The 1s subshell has 2 electrons, and the 2p subshell has 6 electrons. Therefore, the 2p peak (6 electrons) will be three times taller than the 1s peak (2 electrons).

Which of the following best explains why the peak corresponding to the 1s electrons in a PES spectrum has a higher binding energy than the peak for the 2s electrons in the same atom?

A) The 1s subshell contains fewer electrons than a full 2s subshell.

B) The 1s electrons have a stronger interaction with the nucleus because they are closer to it.

C) The 2s electrons are removed first during ionization.

D) The 1s electrons have a higher principal quantum number.

Correct Answer: B

The provided text explains that a PES spectrum relates to the 'interactions between the electrons and the nucleus.' Electrons in the 1s subshell are in the lowest energy level and are closest to the positively charged nucleus, resulting in a stronger electrostatic attraction and thus a higher binding energy compared to electrons in the 2s subshell, which are further away.

A PES spectrum for a neutral element shows three peaks. From highest to lowest binding energy, the relative peak heights are 2, 2, and 5. What is the ground-state electron configuration for this element?

A) 1s²2s²2p⁵

B) 1s²2s⁵2p²

C) 1s²2p²3d⁵

D) 1s⁵2s²2p²

Correct Answer: A

The peak with the highest binding energy corresponds to the subshell closest to the nucleus (1s). Its height of 2 indicates 2 electrons (1s²). The next peak corresponds to the next subshell (2s). Its height of 2 indicates 2 electrons (2s²). The peak with the lowest binding energy corresponds to the outermost subshell shown (2p). Its height of 5 indicates 5 electrons (2p⁵). Combining these gives the ground-state configuration 1s²2s²2p⁵.

The data from photoelectron spectroscopy provides direct evidence for which of the following aspects of atomic structure?

A) The existence of different isotopes for an element.

B) The arrangement of electrons into subshells with distinct energy levels.

C) The total mass of an atom's nucleus.

D) The magnetic properties of an atom.

Correct Answer: B

The provided content states that PES relates the spectrum to the 'ground-state electron configuration of the species' and that peak position relates to the 'binding energy of an electron in a subshell.' The presence of multiple peaks with different binding energies is direct evidence that electrons exist in different subshells, each with a unique energy level.

How would the photoelectron spectrum of a K⁺ ion be different from that of a neutral Ar atom? (Both species are isoelectronic with the configuration 1s²2s²2p⁶3s²3p⁶).

A) The spectra would be identical because they have the same electron configuration.

B) The K⁺ spectrum would have an additional peak compared to the Ar spectrum.

C) All peaks in the K⁺ spectrum would be shifted to higher binding energies compared to the Ar spectrum.

D) All peaks in the K⁺ spectrum would be shifted to lower binding energies compared to the Ar spectrum.

Correct Answer: C

The content states that PES relates to the 'interactions between the electrons and the nucleus.' A K⁺ ion has 19 protons, while an Ar atom has 18 protons. Although they have the same number of electrons, the electrons in K⁺ are attracted by a greater nuclear charge (19+ vs 18+). This stronger interaction results in higher binding energies for all electrons, shifting all peaks to the left (higher energy) on the spectrum.

A student observes a PES spectrum and notes that one peak is twice as high as another. What can the student conclude?

A) The subshell of the taller peak has twice the binding energy.

B) The subshell of the taller peak contains twice as many electrons.

C) The subshell of the taller peak is twice as far from the nucleus.

D) The subshell of the taller peak belongs to a different element.

Correct Answer: B

This is a direct application of the rule provided in the content: 'peak height is proportional to the number of electrons in that subshell.' Therefore, a peak that is twice as high represents a subshell containing twice the number of electrons as the subshell represented by the shorter peak.